I hv PCOS. I take metformin. But only when I take regestrone I get else I dont. My doc asking to take HSG. Will it help? How I get period if blocked?

Not clear question. Don't know what "regestrone" or "HSG" is. Do you mean progesterone? Do you mean HCG? Whatever, you need to take Metformin on regular basis. It will not block your periods. In fact, it may help normalize your cycle. Cycling progesterone, however, will help. You may also be hypothyroid. See Dr. Broda Barnes' book, Hypothyroidism, the Unsuspected Illness. Don't rely on blood tests.